WO2021152077A1 - Encapsulation method - Google Patents
Encapsulation method Download PDFInfo
- Publication number
- WO2021152077A1 WO2021152077A1 PCT/EP2021/052086 EP2021052086W WO2021152077A1 WO 2021152077 A1 WO2021152077 A1 WO 2021152077A1 EP 2021052086 W EP2021052086 W EP 2021052086W WO 2021152077 A1 WO2021152077 A1 WO 2021152077A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- solution
- solvent
- composition according
- polymer
- photochromic
- Prior art date
Links
Classifications
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
- C09K9/00—Tenebrescent materials, i.e. materials for which the range of wavelengths for energy absorption is changed as a result of excitation by some form of energy
- C09K9/02—Organic tenebrescent materials
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
- B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
- B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
- B42D25/30—Identification or security features, e.g. for preventing forgery
- B42D25/36—Identification or security features, e.g. for preventing forgery comprising special materials
- B42D25/378—Special inks
-
- C—CHEMISTRY; METALLURGY
- C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
- C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
- C09D11/00—Inks
- C09D11/50—Sympathetic, colour changing or similar inks
Definitions
- the present invention relates to compositions of encapsulated smart materials, methods of making said compositions and articles or products comprising said compositions, for example inks or coatings to make security documents, and to detect counterfeiting.
- Preferred compositions using a negative photochromic coating are particularly useful as security features.
- the present invention also relates to the use of said compositions in a range of new applications, articles and/or devices with desired material properties and associated methods of making the same.
- Particular examples of compositions of encapsulated materials and articles containing said materials includes inks, documents, anti counterfeiting materials, and systems comprising the same.
- Photochromic substances are substances which undergo a reversible change in colour or shade when exposed to light of a particular wavelength or intensity. Pigments which exhibit colour switching are useful in a number of industrial applications such as anti-counterfeiting, display screens and other optical devices.
- US5807625A describes a security document, banknotes, with reversibly photochromic printing inks.
- US5155607A describes an optical modulation display device and display method in which either a mixture of liquid crystal plus photochromic dispersed in polymer or a liquid crystal dispersed in a photochromic polymer.
- US20120309761A1 provides rapid reverse photochromies due to the ability to control the nano- and micro- environment surrounding the photochromic agent.
- a polymer with interconnected pores (10-100 nm) forms a continuous network.
- the photochromic agent may be contained in the pores in the polymer without leaching as long as some of the internal sections of the pores are narrow enough to trap the photochromic.
- Negatively photochromic materials which are coloured and bleach (go colourless) in light are less well known or used in industry.
- the present inventors have found that the afore-mentioned problems may be addressed by using the encapsulation method devised by the inventors.
- This two- phase encapsulation is applicable for any system where the polymer is immiscible with the material to be encapsulated.
- a problem with some smart materials requiring encapsulation in polymer or resin systems is that functionality is lost due to inability of the molecule to survive direct incorporation into polymers or resin systems, for example Van der Waals bonds causing some molecules (e.g. proteins) to fold in specific geometries are generally not supported in these environments.
- Photochromic coatings are disclosed which are particularly used for the manufacture of security inks and coatings.
- the coatings are normally strongly coloured and become colourless when irradiated by visible radiation such as by daylight. This ‘photo-bleaching’ is reversible.
- Methods in the art can be used to prepare the inks or coatings to make security documents, and to detect counterfeiting.
- the present invention provides a coating composition, preferably inks, comprising a negative photochromic compound which normally have an intense colour and a high degree of photosensitivity and demonstrate a rapid and reversible photo-bleaching on exposure to daylight.
- the present invention provides negatively photochromic coatings and printing inks particularly suited to applications in the field of document security and prevention or detection of forgery.
- the present invention provides methods fortesting documents which have been marked with a print obtained from the coating and printing inks of this invention.
- the present invention provides a rapid reset function to the negative photochromic response, whose colour may be reset under UV irradiation.
- the present invention further provides the production of negatively photochromic coatings by complex coacervation.
- Complex coacervation is known for the development of carbonless copy-paper, and it is now commonly used throughout the pharmaceutical industry.
- the technique involves the use of two oppositely charged polymeric materials, usually gelatine and acacia.
- the core material is dispersed in a solution of gelatine and water above 45°C (where the droplet size is determined by the rate of mixing), and subsequently diluted by a water and acacia solution.
- the material to be encapsulated are of a high purity grade, for example greater than about 95 wt% pure, or greater than about 96 wt% pure, or greater than about 97 wt% pure, or greater than about 98 wt% pure.
- Figure 1 shows a schematic method of preparation of the formulation.
- Figure 2 shows optical microscopy of capsules prepared according to the invention. Detailed Description of the Invention
- ratios include 1:10 preferably 1:8 more preferably 1:5.
- solvent B evaporates faster than solvent A (i.e. polymer should cure before the emulsion loses stability and droplets coalesce), solution 1 and 2 must be immiscible (or very poorly miscible).
- Solution 1 should be concentrated (particularly relevant for photo/thermos/electro- chromic pigments or smart biomaterials e.g. green fluorescent protein (GFP)).
- GFP green fluorescent protein
- Material in solvent A should not have an affinity for the polymer (and vice versa).
- Green Fluorescent Protein GFP
- other proteins offer major opportunities in research and development, in particular in biotechnology and medicinal chemistry.
- Green Fluorescent Protein has been encapsulated in polymer systems according to the present invention and its functional activity demonstrated by measuring its retained fluorescence using optical spectroscopy. Had fluorescence been lost this would indicate denaturing of the protein and that the encapsulation method is not suitable for these systems.
- Image 1 shows capsules after excitation with UV light.
- Image 2 shows capsules after relaxation.
- Example 3 Negative Photochromic
- 0.004 g of spiropyran compound and 4 ml_ of benzyl alcohol were mixed together.
- the core material thus obtained was cooled to 4°C and emulsified into 20 ml_ of a 7 wt% aqueous solution of Mowiol 40-88.
- the emulsification took place using a sonic probe for 3 x 1 minute bursts.
- the mixture was cast into a shape and left to dry over night and day.
- 0.004 g of spiropyran compound and 4 ml_ of toluene were mixed together.
- the core material thus obtained was cooled to 4°C and emulsified into 20 ml_ of a 7 wt% aqueous solution of Mowiol 40-88.
- the emulsification took place using a sonic probe for 3 x 1 minute bursts.
- the mixture was cast into a shape and left to dry over night and day.
- GFP was a useful test material due to the ease of determining whether it has denatured - once denatured, the protein would not fluoresce green.
- GFP was obtained from Sigma Aldrich and from LabGenius (a variant they had engineered to increase durability and strength of fluorescence). GFP samples were sonicated in 2 ml_ Eppendorf tubes - care being taken to be aware of the concentration of polymer since the higher temperatures generated by sonication will cause a small amount of solvent to evaporate rapidly and the material to cure in the tube.
- a UV torch (-395 nm) was used to illuminate the sample and imaged through a yellow filter.
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Organic Chemistry (AREA)
- Life Sciences & Earth Sciences (AREA)
- Wood Science & Technology (AREA)
- Paints Or Removers (AREA)
- Inks, Pencil-Leads, Or Crayons (AREA)
- Compositions Of Macromolecular Compounds (AREA)
Abstract
Description
Claims
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GB2211785.7A GB2606326A (en) | 2020-01-30 | 2021-01-29 | Encapsulation method |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
GBGB2001300.9A GB202001300D0 (en) | 2020-01-30 | 2020-01-30 | Materials and methods |
GB2001300.9 | 2020-01-30 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2021152077A1 true WO2021152077A1 (en) | 2021-08-05 |
Family
ID=69800186
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/EP2021/052086 WO2021152077A1 (en) | 2020-01-30 | 2021-01-29 | Encapsulation method |
Country Status (2)
Country | Link |
---|---|
GB (2) | GB202001300D0 (en) |
WO (1) | WO2021152077A1 (en) |
Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5155607A (en) | 1990-03-16 | 1992-10-13 | Fuji Xerox Co., Ltd. | Optical modulation display device and display method using the same |
US5807625A (en) | 1988-01-12 | 1998-09-15 | Sicpa Holding S.A. | Security document with reversibly photochromic printing inks |
US20120309761A1 (en) | 2009-10-27 | 2012-12-06 | Agency For Science, Technology And Research | Fast-response photochromic nanostructured contact lenses |
EP3389846A1 (en) * | 2015-12-14 | 2018-10-24 | Indizen Optical Technologies Of America, LLC | Nanoemulsion optical materials |
-
2020
- 2020-01-30 GB GBGB2001300.9A patent/GB202001300D0/en not_active Ceased
-
2021
- 2021-01-29 GB GB2211785.7A patent/GB2606326A/en active Pending
- 2021-01-29 WO PCT/EP2021/052086 patent/WO2021152077A1/en active Application Filing
Patent Citations (4)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US5807625A (en) | 1988-01-12 | 1998-09-15 | Sicpa Holding S.A. | Security document with reversibly photochromic printing inks |
US5155607A (en) | 1990-03-16 | 1992-10-13 | Fuji Xerox Co., Ltd. | Optical modulation display device and display method using the same |
US20120309761A1 (en) | 2009-10-27 | 2012-12-06 | Agency For Science, Technology And Research | Fast-response photochromic nanostructured contact lenses |
EP3389846A1 (en) * | 2015-12-14 | 2018-10-24 | Indizen Optical Technologies Of America, LLC | Nanoemulsion optical materials |
Non-Patent Citations (2)
Title |
---|
AIKEN ET AL., DYES AND PIGMENTS, vol. 149, 2018, pages 92 - 121 |
JULIA-LOPEZ ET AL., ACS. APPL. MATER. INTERFACES, vol. 11, 2019, pages 11884 - 11892 |
Also Published As
Publication number | Publication date |
---|---|
GB202001300D0 (en) | 2020-03-18 |
GB202211785D0 (en) | 2022-09-28 |
GB2606326A (en) | 2022-11-02 |
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